var cssPropertySupported = (function () {
    var mem = {}; // save test results for efficient future calls with same parameters

    return function cssPropertySupported(prop, values) {
        if (mem[prop + values]) return mem[prop + values];

        var element = document.createElement('p'),
            index = values.length,
            value,
            result = false;

        try {
            while (index--) {
                value = values[index];
                element.style.setProperty(prop, value);

                if (element.style.getPropertyValue(prop) === value) {
                    result = true;
                    break;
                }
            }
        } catch (pError) {}

        mem[prop + values] = result;
        return result;
    };
})();

if (!cssPropertySupported('display', ['flex'])) {
    fillViewport();
}

function fillViewport() {
    var vh = window.innerHeight * 0.01;

    var main = document.querySelector('main');
    var footer = document.querySelector('footer');
    main.style.minHeight = window.innerHeight - footer.offsetHeight * 2 + 'px';

    window.addEventListener('resize', function () {
        main.style.minHeight =
            window.innerHeight - footer.offsetHeight * 2 + 'px';
    });

    // also hide early android browser's zoom controls
    var meta = document.createElement('meta');
    meta.name = 'viewport';
    meta.content =
        'width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no';
    document.getElementsByTagName('head')[0].appendChild(meta);
}